NAIROBI -- In the last 40 years, Nairobi has made great strides in reducing its national fertility rate -- the average number of children a Kenyan woman bears in her lifetime -- from about eight children per woman to just under five, according to World Bank and Kenyan government statistics.

The country now has the second-lowest fertility rate in East Africa, behind Burundi, while neighboring Somalia and Uganda average around six children per woman.

Although the demographic change is part of Kenya's strategy to promote sustainable population growth, families are still having more children than they want.

According to Boniface K'Oyugi, director general of Kenya's National Council for Population and Development, Kenyans historically had more children based on the assumption that some would inevitably die young. Improved public health services, however, have reduced child mortality rates.

“According to the latest demographic and health survey, both men and women desire to have four children on the average, but they are actually having five children," he says, explaining that Nairobi is targeting an average national fertility rate of three children per woman by 2030, with hopes of ultimately reaching the average at which the population with stabilize -- around two children per women.

Education, especially for women, he says, is the key.

“From the demographic and health survey data we have, girls that have gone beyond secondary-education level generally give birth to fewer children by the time they complete their reproductive ages, as compared to their counterparts who never went to school," he says.

While Kenya is using public health clinics and youth-friendly programs to educate the population about birth control and maternal-care options, socio-economic progress is also shaping perceptions of family size.

Although it was once considered cost effective to produce many children to work and give money back to the parents, for example, money now flows the other way.

"If the direction of the wealth is mainly from the parents to the children, the fewer children you have the better [off] you are as a parent," says K'Oyugi.